Over the past years, much work has been done to try and make hybrid-electric vehicles (HEVs) a viable alternative to non-hybrid vehicles. Hybrid-electric vehicles are often classified as being “series hybrid” or “parallel hybrid”. In a series hybrid HEV, an engine turns a generator, and the generator is used to power one or more electric motors with rotation of the motor shaft(s) being used to move the vehicle. In many instances, the generator is also used to charge on-board batteries, which are used to supplement power provided by the generator during heavy load conditions, and to store energy recovered via regenerative braking.
In some instances, a turbine engine is used to turn the generator, which may be a permanent magnet generator, as described in U.S. Pat. No. 6,683,389, and U.S. Pat. No. 5,568,023. Unfortunately, previous apparatus and methods used in series hybrid HEVs tend to have substantial hardware and production costs, have less than optimum reliability, and have excessive volume and weight. As such, there is a need for improved HEVs.